（425×5770+4225×425）÷125÷8
=425×(5770+4225)÷(125×8)
=425×9995÷1000
=(10000-5)×425÷1000
=10000×425÷1000 - 5×425÷1000
=4250-2125÷1000 (5×425就直接算呗,没什么好分解的了)
=4250-2.125
=4247.875